The present invention relates to a magneto-optical recording medium for use as a magneto-optical memory, a magnetic recording and display cell and so forth, and more particularly to a magnetic thin film recording medium which has an easy axis of magnetization in a direction perpendicular to the film surface and permits recording of a bit of information by forming an inverted magnetic domain of a circular or any other arbitrary configuration and reading out of the information through utilization of the magnetic Kerr effect.
With ferromagnetic thin films which have an easy axis of magnetization in a direction perpendicular to their film surface, it is possible to create a small inverted magnetic domain of a magnetic polarity reverse from a homogenous magnetization polarity in the film surface homogeneously magnetized with the south or north magnetic pole. By making the presence and absence of such an inverted magnetic domain correspond to a "1" and a "0" in digital form, respectively such ferromagnetic thin films can be employed as high density magnetic recording media. These ferromagnetic, vertically magnetized films are typified by, for example, Gd-Co, Gd-Fe, Tb-Fe, Dy-Fe, GdTbFe, etc. as amorphous rare earth transition metal alloy thin films, MnBi as a polycrystalline metal thin film and GIG as a compound single crystal thin film.
However, since their Curie temperature or magnetic compensation temperatures are high, a large recording power is needed and, at present, high speed recording by the use of a semiconductor laser is impossible.